The Open Grave

From Author Wars - https://authorwars.com/publications/the-open-grave-500824.html

Overview:

Title: The Open Grave
Author: Alan Hull Walton
Year: 1971
ISBN-10: 0800858352
Publisher: Taplinger
Price: $5.95
Pages: 233
Binding: Hardcover
Type: Non-fiction
Title Reference: Schalken the Painter
Notes: Data from Amazon and from WorldCat. WorldCat lists it as "[1971, © 1969]". Since it is copyright 1969, some sources list it as being published in 1969. The 1971 publication appears to be the first publication. Published with dust jacket.
Note on 2021-03-29: A Spearman 1969 edition appears to be the real first publication. A cover can be found on Amazon. "Jacket Designed by Rus Anderson" on front flap seen on eBay. Starting page number for the Le Fanu story from a copy on Google Books.